SE-1

Step 1: I first thought of a basic approach where I would store visited nodes and check if a node appears again while traversing the linked list.
Step 2: The interviewer asked me to optimize the solution and reduce extra space usage.
Step 3: I then applied Floyd’s Cycle Detection Algorithm using slow and fast pointers, where the slow pointer moves one step and the fast pointer moves two steps. If a cycle exists, both pointers eventually meet.
Step 4: I explained the time complexity as O(n) and space complexity as O(1), which satisfied the interviewer.

Step 1: I initially considered checking all possible substrings and verifying whether they contain unique characters, but this approach was inefficient.
Step 2: The interviewer asked me to optimize the solution.
Step 3: I used the sliding window technique with a data structure to track visited characters, expanding the window when characters are unique and shrinking it when repetition occurs.
Step 4: I explained how this approach works in linear time O(n), and the interviewer was satisfied with the optimized solution.

Step 1: I first understood the problem and considered a simple approach of traversing the linked list until the Nth node and deleting it, but this required careful handling of edge cases.
Step 2: The interviewer asked me to optimize and handle cases like deleting the head node efficiently.
Step 3: I used a two-pointer approach where one pointer is moved N steps ahead, and then both pointers are moved together until the first pointer reaches the end.
Step 4: At that point, the second pointer points to the node just before the Nth node, which can be removed by updating the next pointer.
Step 5: I explained the time complexity as O(n) and space complexity as O(1), and discussed edge cases like N equal to the list length.

Tip 1: Focus on understanding core concepts and logic before jumping to code or queries.
Tip 2: Practice problem-solving regularly, especially linked list problems and SQL queries.
Tip 3: Analyse edge cases and explain your approach clearly while solving problems.